Complete the evaluation of the nutritional status of a group of patients participating in a comparative study of peritoneal and hemodialysis. Complete the study of selected metabolic issues in peritoneal, CAPD, and hemodialysis patients. Complete the special studies on the evaluation of peritoneal dialysis in patients with end stage diabetic nephropathy. In patients maintained on peritoneal dialysis, speifically CAPD, conduct additional studies of potassium balance. Study possible causes of the observed large fecal losses of potassium, including the influence of dietary potassium, and levels of insulin and aldosterone.